ICS840004-01 Datasheet, PDF (1/13 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO LVCMOS/LVTTL FREQUENCY SYNTHESIZER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS840004-01
FEMTOCLOCKS™ CRYSTAL-TO-
LVCMOS/LVTTL FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
FEATURES
The ICS840004-01 is a 4 output LVCMOS/LVTTL
ICS
Synthesizer optimized to generate Ethernet
HiPerClockS™ _{reference clock frequencies and is a member of}
the HiPerClocks^TM family of high performance
clock solutions from ICS. Using a 25MHz, 18pF
parallel resonant crystal, the following frequencies can be
generated based on the 2 frequency select pins (F_SEL1:0):
156.25MHz, 125MHz, and 62.5MHz. The ICS840004-01 uses
ICS’ 3^rd generation low phase noise VCO technology and can
achieve 1ps or lower typical random rms phase jitter, easily
meeting Ethernet jitter requirements. The ICS840004-01 is
packaged in a small 20-pin TSSOP package.
• Four LVCMOS/LVTTL outputs,
15Ω typical output impedance
• Selectable crystal oscillator interface
or LVCMOS/LVTTL single-ended input
• Output frequency Range: 56MHz - 175MHz
• VCO Range: 560MHz - 700MHz
• RMS phase jitter at 156.25MHz (1.875MHz - 20MHz):
0.52ps (typical) design target
Phase noise:
Offset
Noise Power
100Hz ............... -94.9 dBc/Hz
1kHz ............. -119.6 dBc/Hz
10kHz ............. -128.9 dBc/Hz
100kHz ............. -129.2 dBc/Hz
• Full 3.3V or 3.3V core/2.5V output supply mode
• 0°C to 70°C ambient operating temperature
• Available in both standard and lead-free RoHS-compliant
packages
FREQUENCY SELECT FUNCTION TABLE FOR ETHERNET FREQUENCIES
F_SEL1
0
F_SEL0
0
Inputs
M Divider N Divider
Value
Value
25
4
M/N
Ratio Value
6.25
Output Frequency
(25MHz Ref.)
156.25
0
1
25
5
5
125
1
0
25
10
2.5
62.5
1
1
25
5
5
125
BLOCK DIAGRAM
OE ^Pullup
F_SEL1:0 ^{Pullup:Pullup}
nPLL_SEL ^Pulldown
nXTAL_SEL ^Pulldown
XTAL_IN ^25MHz
OSC ⁰
XTAL_OUT
TEST_CLK ^Pulldown
1
2
Phase
Detector
VCO
F_SEL1:0
1
N
0 0 ÷4
0 1 ÷5
0
1 0 ÷10
1 1 ÷5
M = ÷25 (fixed)
PIN ASSIGNMENT
F_SEL0 1 20 F_SEL1
nc ^{2 19} GND
nXTAL_SEL ^{3 18} Q0
TEST_CLK ^{4 17} Q1
OE ⁵
1 6 _VDDO
MR ^{6 15} Q2
nPLL_SEL ^{7 14} Q3
VDDA ⁸
13 _GND
nc ^{9 12} XTAL_IN
Q0
VDD ^{10 11} XTAL_OUT
ICS840004-01
Q1
20-Lead TSSOP
6.5mm x 4.4mm x 0.92mm
Q2
package body
G Package
Q3
Top View
MR ^Pulldown
The Preliminary Information presented herein represents a product in prototyping or pre-production. The noted characteristics are based on
initial product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications
without notice.
840004AG-01
www.icst.com/products/hiperclocks.html
REV. B JANUARY 3, 2006
1